Apparatus for treating filaments.



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32 I 32 n 3o IlIn IV 5 /HF a G Hf UNITED sTATEs PATENT oEEIoE.

WILLIAM D. COOLIDGE, 0F SCHENECRADY, NEW YORK, ASSIG'NR TO GENERAL t' ELECTRIC COMPANY, A CORPORATIONI 0F NEW YORK.

APPARATUS Fon TREATING FILAMENTS.

To all whom it may concern Be it known that I, WILLIAM D. CooLInoE, a citizen of the United States, residing at Schenectady, county of Schenectady, State of New York, have invented certain new and useful Improvements in Apparatus for Treating Filaments, of which the following is a specification.

This `invention comprises an apparatus for the production of incandescent lamp filaments by treatment of wire.containing rcfractory material.

The apparatus is in many respects automatic and is adapted. for operation on a roll of ductile wire to produce iilalnents properly shaped and properly treated for mounting in incandescent lamps.

I have found that non-ductile material, such as tungsten and other refractoryv elements or compounds, may be incorporated in a ductile alloy, such as cadmium amal gam, and that the product so formed may be extruded into ductile wires of small crosssection. pose may contain fifty parts of mercury to fifty parts of cadmium, and the tungsten powder or other refractory component of the squirting mixture may be added to the amalgam in the proportion of thirty-nine per cent. byv weight. The amalgam is warmed to a pasty condition and the tungsten is introduced therein by rubbing the mixture in an ordinary chemists mortar. The mixture can be extruded t-hrou h a diamond die when slightly warmer. Such ductile wire and the method ot producing it form the subject of my application, Serial No. 377,781, filed June 7, 1907.

According to my present| invention I make lamp tilaments from the ductile wire above described, or from other ilamentary conductor requiring similar treatment, by use of an apparatus such as is shown in the accompanying drawings.

Figure 1 is a sectional elevation of a chamber in which the treating` operation is carried on. Certain of the elements are represented diagrammatically; Fig. 2 is a diagram illustrating the time during which the several circuits carry current; and Fig. 3 is a diagram to illustrate how the circuits are controlled from a single rotating shaft.

The apparatus illustrated in Fig. 1 comprises an envelop 1 of glass or metal provided 'with a cover 2 cemented thereto or made tight by means of a suitable gasket.

Specification of Letters Patent.

' Application led February 13, 1907, Serial No. 857,141.

An amalgam suitable for this pur-f Patented May 14, 1912.

Renewed January 27, 1911. Serial No. 605,074.

This chamb'er is provided with an outlet 3 by which connection may be made with an a1r pump and through which the chamber may be exhausted. Within this chamber is supported a reel 4 carrying a considerable uantity of ductile wire such as that above escribed. Cooperating with the reel are means for unwindin'g the wire, for looping it up in a straight loop, for passing a small current through the loop to drive out the4 mercury and cadmium, for increasing the current to sinter the residue into a coherent body, for disconnecting therfinished loop from the untreated Wire and dropping it into asuitable receptacle, and for repeating these operations in regular order until the Wire on the reel has been converted into iilaments. The specific means for carrying out these various acts are hereinafter set forth in more detail.

When the apparatus is set up, the outer end of the coil of wire on the reel is threaded through a small but rigidly mounted eye 5 and passed between rollers 6 and 7. These rollers are mounted at the ends of movable levers 8 and 9 pivotally supported on axes l0 and 1].and geared together so that when arm 8 moves up arm 9 moves down and the rolls 6 and 7 separate. A coiled spring 12 initially holds the rollers in contact on the ductile wire. Immediately in 'front of the movable rollers and in direct line with the wire is a tweezer-sha ed spring clip 1B mounted on the end o a movable arm 14. This clip is adapted to move forward and take hold of the end of the ductile wire and then recede for a distance of ten or twelve inches to unwind the ductile wire from the spool. The'clip is then restored to its initial position and the filament sags down in the form of a loop 15', as shown in the drawings. To secure this movement of the spring clip 13, anl electromagnet 16 is provided, with suitable levers connecting with the movable arm 14 on which the spring clip is mounted. These connections consist of a lever 17, pivoted at 18 and having a lower slotted end 19 engaging with a pin located a short distance above the pivotal point 20 of arm 14. A coiled spring 21fengages with lever 17 and tends to kee arm 14 in the lowered position indicated 1n dotted lines in the figure. This tendency is `counteracted by the pull of electromagnet '16 during the entire cycle of treatment, except for that particular part during which the wire is to I vare held apa be unreeled and shaped into a loop. Dur-A ing that interval the electromagnet is unenergized and the sprin is free to move the arm 14 and its attache clip.

Assuming that the ductile wire on spool 4 has been threadedthrough the eye 5 and projects as yfar as the rollers )6 and 7, the operation ofthe `device is as follows: Av strong current is passed through elect-romagnet 16 to cause the tweezer-shaped clip 13 to approach the end of the duetile wire. As it 'does so it passes under the influence of electromagnet-22 and the latter attracts an armature 23 carried on the clip and thereby opens the clip, so that the wire may pass in betweenthetwo lips of the clip. At this stage of the o eration the rollers 6 Aand 7 by the action of electromagnet 24 on thev pivoted arm 8. The clips` are free to move up some little distance along the wire. This movement is subject to the retarding action' of a at spring 26 carried I 0n arm 14 and put under compression by a rigidly mounted stud 27.V A set-screw 28 controls the limit of movement. When the clip reaches a position well up on the wire,

. the electromagnet 22 is denergized and the two jaws or lips of the clip 13 come together on the Wire and take a rm hold thereon.

Electromagnet 16 is then denergized and coiled spring 21 operates through' the con nected levers and arns to swing clip 13 around through an are into the position shown in dotted lines, thereby unreeling a considerable length of ductile wirefrom reel 4. Two pads of felt 28 serve to control the unreeling of the wire. The felt pads 28 are stationary except for the 'Spring support of the upper one and pinch lightly on the amalgam wire passing between them. There is also a spring bearing on theitop of the reel 4, as shown in the drawing, 'ywhich also to some extent controls the unreeling of the wire, both this spring and the felt pads serving to keep the wlre from shooting by or crowding on through loop; 5 after the regular length of wire has been pulled outl by the spring clip 13. Immediately after the unreeling of the wire, electromagnet 24 is denergized, and rollers 6 and 7 approach each other and engage with the wire.'l Electromagnet 16 is then energized with a relatively weak current to bring the clip into Athe position shown in the drawing and to form a loop out of the unreeled wire. Current is then passed through the filament by Way of arm 8, roller 6, clip 13, and'arm 14 and the filament is heated at a low temperature until the mercury and cadmium distill therefrom'. A water-cooled jacket 25 may be utilized for condensing the va orizable components ,of the wire. This jacket is shaped like a half moon and extends on three sides of the filament to condense the metal vapors given off during the heat treatment. The current is then automatically increased and the filament brought quickly to bright incandescence, in which condition it is maintained for a short time to insure vaporization of all easily Vaporizable components and sintering of the refractory particles of which the wire is composed. The

ately below and'remains there until the entire reel of wire has been worked up and untll the t-reatmg chamber 1s opened to reoeiv'e a new reel 'of w1re. The easy release or disconnection of aftreated loop from the supply of untreated Wire may be attributed to the fragile nature of that ortion of the wire `in contact with the rol ers and with the clip. The thermal conductivity ofthese parts is suflicient tov prevent complete sinteringof the'portions in immediate contact, and these portions are therefore much weaker than the filament itself.

I have above indicated a certain sequence in the excitation of the several electromagnets and circuits, and I yhave indicated in Fig. 1 a rotating shaft-30 provided with colnlnutators for carrying out these steps. Each of the six commutators mounted on this shaft is provided with a segment of conducting material connected with the shaft and having an angular width proportional to the tiine/ during which the particular circuit controlled vby that commu# tator is to receive current. A common source of electrical energy 431 may be elnl yA commutator 33 supplies current to electromagnet- 24 to separate `rollers 6A and 7. Commutators 34 and 35 control currentl to electromagnet 16 and serve to give it a weak current to hold clip 13 in the position shown in the drawing, or to give ita strong current to force the clip forward toward the rollers, or lastly, to` give it no current at lall so that spring 2l mayswing the clip through a long arc. Commutator 36 controls the current to the electromagnet 22 for opening the jaws of the spring clip .13. Commutators 37 and 38 control the current through the filament itself and give it a weak current during the 'pearly stage of treatment, and high current during subse uent stages.

Figs. 2 an 3 illustrate diagrammatically the magnitude and relation of the time 1ntervals during 4which the several circuits are energized. This diagram is intended/tot@ l show how the various switch or commutator segments should be proportioned and arranged in order to automatically energize the electromagnets, etc., at such time intervals as will enable them to carry out the series of acts resulting in finished filaments. The sectors on Fig. 2 having angular Widths corresponding to time intervals and having radii indicative of the magnitude of current 1n the several circuits and are numbered to correspond with the electromagnets and filament of Fig. 1. A circuit is simultaneously established through electromagnets 22 and 24 and very shortly thereafter through electromagnet 16. The last namedelectromagnet is energized by strong current. Then electromagnet 22 is denergized to permit the spring clip 13 to engage with the pro' truding end of ductile. wire; then electromagnet 16 is denergized to permit the spring clip to swing through an arc.

Shortly thereafter electromagnet 24 is denergized to permit rollers 5 and 6 to contact with the wire. Electromagnet 16 is then energized with a smaller current to restore the clip to its initial position. Simultaneously, or shortly thereafter, the filament 15 receives a low current to vaporize the mercury and cadmium. After a brief interval current through filament 15 is 'increased to sinter the tungsten or other refractory material into a coherent and strong filament. Throughout the entire time of filament treatment electromagnetlti is energized to hold the clips in the position'shown in the draw ings.

Fig. -illustrates an arrangement of commutators suitable. for producing the effects above recited.

What I claim as new, and desire to secure by Letters Patent of the United States, is,-

1. TheV combination of a container, means for exhausting the air therefrom, a spool of ductile wire within said'container, means for unreeling a section of said Wire and for shaping it into a loop, means for supplyin current-'to said loop to treat the same, and means for separating the treated loop from the untreated wire.

2. The combination of a container, asupply of ductile wire therein, automatic means for, forming a portion of said wire into a loop, means for supplyin current to said loop to produce changes t erein, and means for separating the treatedloop from the supply of wire.

3'. The combination of a container, a supply of ductile Wire therein, and automatic means for treating successive portions of said wire wit-h current and for separating said portions. y

4. The combination with a'sealed envelop, a reel of Wire therein, means for unreeling a predetermined length of said wire and for shaping it into a loop, means for supplying a relatively low current to said loop, automatic means for increasing the current to heat the loop to incandescence, and means for releasing the treated loop to make room 'for a second length of wire.

, 5. The combination of a sealed envelop, a ductile conductor therein, means for shaping a predetermined length of said conductor into a loop,' means for supplying current thereto to treat the conductor, and automatic means for repeating this treatment on successive lengths of said conductor.

6. The combination of a container, a supply of unfinished filamentary conductors therein, and automatic means for successively incandescing portions of said Suppllly with current passed therethrough while container remains sealed.

7. The combination of a sealed container, a supply of unfinished filamentary conductors, automatic means for successively moving redetermined and equal lengths of said conf uctor into position for treatment with current iii said sealed container, and means for supplying a sintering current to the con` ductor under treatment.

8. The combination of a container, means for removing the air therefrom, a supply of unfinished filamentary conductors containin refractory material within said container, and automatic means for successivelyl producing sintered filaments from s aid supply of unfinished conductors while the container is maintained free from oxygen.

9. In an apparatus for the continuous treatment of filament, the combination of a source o'f raw filament containing a binder, means for taking raw filament from such source and giving it the general shape which it is desired that the finished filament should have,` and means for treating such shaped raw filament first at low temperature and then at high temperaturetoeliminate the binder therefrom and sinter the final material of the filament.

10. In an ap aratus for the continuous treatment of re ractory metal filament, the combination of a source of raw filament containing binder, means for feedin said raw filament from said source, means or passing through successive portions of said raw filament as it is fed from the source first a relatively expel the binder and then a higher current to sinter the final refractory metal.

In witness whereof, I have hereunto set my hand this 12th day of February, 1907.

WILLIAM D. COOLIDGE.

Witnesses:

BENJAMIN B. HULL, HELEN Carolin.

low current to heat it sufiiciently vto v 

